Changing α: Type I vs. Type II errors
A researcher lowers the significance level from 0.05 to 0.01 without changing the sample size. What is the effect?
Answer D: explanation for every choice
A
Reducing both error rates at once requires more information, such as a larger sample.
B
Power is 1 − β. A stricter α lowers power.
C
Alpha is the Type I error rate, so lowering it reduces Type I errors.
D
Correct. A stricter threshold makes false positives less likely but makes real effects harder to detect.
TakeawayLowering α trades fewer false positives for more false negatives.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID ps153.